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Combat Aircraft of the Pacific War

Kawasaki Ki-61 Hien'Tony'
Ki-61-IIb Hien in the markings ot the 244th. Sentai 2nd Chutai (Tokyo Defence Area, 1945)

In 1937 Kawasaki purchased a licence to build the German DB.601 engine - the resulting revised and lightened Japanese engine emerged in 1940 as the Ha-40.

Around this engine Kawasaki planned the Ki-60 fighter, and a lighter aircraft designated the Ki-6 Hien ('Flying Swallow').  The latter was completed in December 1941, and flew well, reaching a speed of 368 mph.  During the first half of 1942  the prototype was extensively tested, performing very well against a captured P-40E Warhawk and a German Messerschmidt Bf-109E sent to Japan by submarine.

The submarine also brought 800 Mauser MG151 cannon, which were fitted to the early Ki-61s despite the unreliable supply of electrically-fired ammunition for this weapon.

The Gifu plant delivered 2,654 (or, according to one source, 2,750) of the Ki-61-1 and -1a versions - the latter being redesigned for easier servicing and increased manouevrability.  They went into action around New Guinea in April 1943 and were given the reporting-name 'Tony' by the Allies. They were the only Japanese fighters with a liquid-cooled engine.

In 1944 the Ki-61-II was being built, but was only trickling off the production lines, and was suffering from the unreliability of its engine. Moreover the engine was not being produced in sufficient numbers.  The initial version of the -II had a larger wing and a new canopy, but it was soon replaced by the -IIa with the older and proven wing.  Only 374 of all variants of the -II were built.

In early 1945 one of 275 engineless airframes was fitted with the Ha-112 radial engine.  Although a sudden lash-up conversion this produced a staggeringly fine fighter, by far the best ever produced in Japan.  This aircraft, designated the Ki-100, was put into production with desperate haste.  One of the first Ki-100 units destroyed 14 F6F Hellcats over Okinawa in their first major encounter - without loss to themselves.  The easily-flown and serviced Ki-100 fought supremely well against Allied fighters and B-29 bombers to the very end of hostilities in the Pacific.


Kawasaki Kokuki Kogyo

Single-seat fighter

Span: 39' 5" (12 metres)Length: (Ki-61-1) 29' 4" (8.94 metres) (Ki-61-II) 30' 1" (9.16 metres)

(K-61-I) One 1,175 hp Kawasaki Ha-40 inverted-vee 12- cylinder ( liquid-cooled)
(Ki-61-II)  One 1,450 hp Kawasaki Ha-140 inverted-vee 12-cylinder (liquid-cooled)

(Ki-61-Ia) 2 x 20mm MG151/20 in wings,  2 x  12.7 mm mchine guns above engines
(Ki-61-IdAs with K-61-Ia but with 30mm cannon in wings
(Ki-61-II) Four x 20 mm Ho-5 cannon in wings

Maximum speed (Ki-61-I) 348 mph (560 km/hour) (Ki-61-II) 379 mph (610 km/hour)
Initial climb (All Ki-61 versions) 2,200 feet (675 metres) per minute
Service ceiling (Ki-61-I) 32,800 feet (10,000 metres) (Ki-61-II) 36,100 feet (11,000 metres)

First flight (Ki-60) March 1941  (Ki-61) December 1941  (Ki-61-II) August 1943
Service delivery (Ki-61-I) August 1941

Nakajima Ki-84 Hayate 'Frank'

Grumman F6F Hellcat - US Navy fighter

Republic P-47 Thunderbolt - US Army fighter

Pacific Aircraft - Index

The Battle of the Philippine Sea,  19-20 June 1944

The Battle for Leyte Gulf,  23-26 October 1944

Dave James' Naval and Maritime Pages



 The main source for the this page was Bill Gunston's
"Combat Aircraft of World War II" (Salamander, London 1978).
The illustration of the Ki-61 is reproduced with thanks from the same source.